HOXA-10 expression in the mid-secretory endometrium of infertile patients with either endometriosis, uterine fibromas or unexplained infertility

The aim of this study was to investigate HOXA-10 expression in endometrium from infertile patients with different forms of endometriosis; with uterine fibromas, or with unexplained infertility and from normal fertile women. Expression levels of HOXA-10 mRNA and protein in endometrium were measured during the mid-secretory phase. This study utilized laser capture microdissection, real-time RT-PCR and immunohistochemistry. HOXA-10 mRNA and protein expression levels in endometrial stromal cells were significantly lower in infertile patients with different types of endometriosis (deep infiltrating endometriosis, ovarian endometriosis and superficial peritoneal endometriosis), with uterine myoma, and unexplained infertility patients as compared with healthy fertile controls. HOXA-10 mRNA expression levels of microdissected glandular epithelial cells were significantly lower than those of microdissected stromal cells, without significant differences among the different groups. No protein expression was detected in glandular epithelial cells. The percentage of patients with altered protein expression of HOXA-10 in stromal cells were significantly higher in patients with only superficial peritoneal endometriosis (100%, 20/20, P < 0.05) compared with the other infertile groups (deep infiltrating endometriosis: 72.7%, 16/22; ovarian endometriosis: 70.0%, 14/20; uterine myoma: 68.8%, 11/16; unexplained infertility: 55.6%, 5/9). The present findings suggested that altered expression of HOXA-10 in endometrial stromal cells during the window of implantation may be one of the potential molecular mechanisms of infertility in infertile patients, particularly in patients with only superficial peritoneal endometriosis. One of the underlying causes of infertility in patients with only superficial endometriosis may be altered expression of HOXA-10 in endometrial stromal cells.